You could just use onion services to to hide the server, and store some backup onion services (whose private keys are kept offline) within the application or its files. When the server goes down due to seizure, you spin up a new one under the backup service's pubkey, and sign a list of new backup keys which will also be kept offline until the next seizure.
You could also combine encryption with steganography, if you strip non-random 'protocol information' from your encrypted bits. Doing that, it would not be easy to prove that you are sending encrypted messages at all without having obtained your keys.
If you just want to track a few individuals... Enumerate all those who possess the data. Now look for data brokers that they deal with (as commenter korse said) and recurse. Find all the employees of every company in question. Muster a few hundred bucks or so, seems to be the market price, and there you go[0].
For research I dunno. You'd probably have to make a deal directly with one of these companies, one way or another, so I would start by talking to them.
> It helps to think of it this way, if it touches your phone or the internet in any way, it's part of the public record. No matter what app you were using. So be cognizant of that, it can come back to bite you 10 years later in ways you never would have imagined.
Meh. If that's the case, why bother caring at all? Bring it on!
What you need to do is pick an entity that has the information you desire, and recursively enumerate the graph of all business deals which involve the sale of that information (their downstreams, effectively). After that, you do OSINT to map out all of the employees of every organization that has access to these databases. After you have mapped out these tens of thousands of individuals and their likely social graphs, all you have to do is pay one of them a relatively small sum to do a query on your behalf.
No, because it is possible establish a token required for access to an onion service on top of the obscurity of having to actually discover the service's public address.
It is also extremely likely that said adversaries control most of Tor, considering that the main mechanisms of tracing Tor circuits do not require control over any nodes of the Tor network whatsoever- snooping on IXPs and as many autonomous systems and underwater wires as possible.
Why would peer to peer cash a la Monero die as long as you can make a connection with TLS though? You probably refer to the uninformed retail investor hype more than anything else.
You could also combine encryption with steganography, if you strip non-random 'protocol information' from your encrypted bits. Doing that, it would not be easy to prove that you are sending encrypted messages at all without having obtained your keys.